Trying to create an event registration form with conditional formatting.

I'm trying to create a registration form for a weekly recurring event that my company hosts - We would use the form for each week/event, but we want to limit users to registering only once - we don't want them to be able to register for every event, every week. Only once per summer or "life of the form." 

Is there a widget that I can customize to do that?

You can set a submission restriction based on a unique field like email. With this restriction, the same email address can not be able to submit your form. Please follow these steps to set a unique question restriction.
1. Go to your form settings.2. Set the unique question option as "Email".You can find more information about the unique question feature from this link.
How to Set Unique Submissions on a Form

Awesome! Thanks so much Alan_D